At times it is necessary to sample or remove a portion of tissue from humans or animals in the diagnosis and treatment of patients with suspicious lesions or areas of tissue, whether they are cancerous or malignant. If the patient has cancer, such as cancer of the breast, there is an advantage for early detection and diagnosis through the use of screening techniques, such as physical examination, or mammography. Mammography is capable of detecting small abnormalities, which are often not palpable during physical examination. A physician determines through mammography, ultrasound or other screening techniques when a biopsy must be performed. A biopsy may be performed by an open or percutaneous technique. Open biopsy is an invasive surgical procedure involving cutting into the suspicious tissue and directly visualizing the target area to remove the entire mass or a part of the mass. Percutaneous biopsy is usually done with a needle-like instrument through a small incision performed with the aid of an imaging device such as X-ray, ultrasound, MRI or the like, and may utilize either a fine needle aspiration or a core biopsy. Core biopsy is extremely useful in a number of conditions and is being used more frequently by the medical profession.
To arrive at a definitive tissue diagnosis, intact tissue is needed from an organ or lesion within the body. In most instances, only part of the organ or lesion need be sampled. However, the portions of tissue obtained must be representative of the organ or lesion as a whole. In the past, to obtain tissue from organs or lesions within the body, surgery had to be performed to locate, identify and remove the tissue. With the advent of medical imaging equipment (X-rays and fluoroscopy, computed tomography, ultrasound, nuclear medicine, and magnetic resonance imaging) it became possible to identify small abnormalities even deep within the body. However, definitive tissue characterization still requires obtaining adequate tissue samples to characterize the histology of the organ or lesion.
For example, mammography can identify non-palpable (not perceptible by touch) breast abnormalities earlier than they can be diagnosed by physical examination. Most non-palpable breast abnormalities are benign; some of them are malignant. When breast cancer is diagnosed before it becomes palpable, breast cancer mortality can be reduced. However, it is often difficult to determine if pre-palpable breast abnormalities are malignant, as some benign lesions have mammographic features which mimic malignant lesions and some malignant lesions have mammographic features which mimic benign lesions. Thus, mammography has its limitations. To reach a definitive diagnosis, tissue from within the breast must be removed and examined under a microscope. Prior to the late 1980""s, reaching a definitive tissue diagnosis for non-palpable breast disease required a mammographically guided localization, either with a wire device, visible dye, or carbon particles, followed by an open, surgical biopsy utilizing one of these guidance methods to lead the surgeon to the non-palpable lesion within the breast.
One type of image-guided breast biopsy instrument currently available is a vacuum-assisted automatic core biopsy device. One such successful biopsy device is shown and disclosed in U.S. Pat. No. 5,526,822 to Burbank et al, which is expressly incorporated by reference herein. This device, known commercially as the MAMMOTOME(trademark) Biopsy System, which is available from Ethicon Endo-Surgery, Inc., a division of Johnson and Johnson, has the capability to actively capture tissue prior to cutting the tissue. Active capture allows for sampling through non-homogeneous tissues. The device is comprised of a disposable probe, a motorized drive unit, and an integrated vacuum source. The probe is made of stainless steel and molded plastic and is designed for collection of multiple tissue samples with a single insertion of the probe into the breast. The tip of the probe is configured with a laterally-disposed sampling notch for capturing tissue samples. Orientation of the sample notch is directed by the physician, who uses a thumbwheel to direct tissue sampling in any direction about the circumference of the probe. A hollow cylindrical cutter severs and transports the tissue samples to a tissue collection chamber for later testing.
Co-pending U.S. patent application Ser. No. 09/057,303, which is expressly incorporated by reference herein, discloses apparatuses and methods for precisely isolating a target lesion, resulting in a high likelihood of xe2x80x9ccleanxe2x80x9d margins about the lesion. This advantageously will often result in the ability to both diagnose and treat a malignant lesion with only a single percutaneous procedure, with no follow-up percutaneous or surgical procedure required, while minimizing the risk of migration of possibly cancerous cells from the lesion to surrounding tissue or the bloodstream. Various tissue acquisition instrument embodiments are disclosed for segmenting the target tissue, including embodiments wherein the instrument comprises a cutting element which is extendable radially outwardly and movable circumferentially to define a peripheral margin about a tissue sample, and other embodiments wherein the cutting element is extendable radially outwardly and movable axially to define peripheral margins about the tissue sample.
Co-pending U.S. patent application Ser. No. 09/196,125, which is expressly incorporated by reference herein, discloses tissue acquisition systems and methods that include radio frequency (RF) cutter loops which are extendable out of a cannula to cut cylindrical tissue samples from a tissue of interest in a patient. The cannula includes inner and outer cannulae which are mutually rotatable and include cutouts through which the cutting loop can be rotated and longitudinally extended to perform the cuts. The tissue samples are then aspirated proximally through the cannula for collection.
According to a first exemplary embodiment of the present invention a tissue acquisition device useful in retrieving tissue samples from a patient comprises a cannula that has a longitudinal axis and a lumen extending along the longitudinal axis and a distally located electrode that has a lumen that is coaxially aligned with the cannula lumen, the electrode is fixedly attached to and is located adjacent to the cannula.
According to a second exemplary embodiment of the present invention, a system for sampling tissue from a patient comprises a RF energy generator capable of generating RF energy and a tissue acquisition device that includes a cannula that has a longitudinal axis and a lumen extending along the longitudinal axis and a distally located electrode that has a lumen that is coaxially aligned with the cannula lumen, the electrode is fixedly attached to and is located adjacent to the cannula and is in electrical communication with the RF energy generator.
According to the third exemplary embodiment of the present invention, a method of sampling tissue from a patient comprises the steps of inserting a cannula into tissue of a patient, the cannula includes an electrode coaxially aligned with and fixedly attached to the cannula, and separating the tissue by advancing the cannula through the tissue of a patient.
Still other objects, features, and attendant advantages of the present invention will become apparent to those skilled in the art from a reading of the following detailed description of embodiments constructed in accordance therewith, taken in conjunction with the accompanying drawings.